


The Demon Returns

by IntrovertedbutBooksmart



Category: Undertale (Video Game)
Genre: Emotional Hurt/Comfort, F/F, Light Angst
Language: English
Status: In-Progress
Published: 2016-07-07
Updated: 2016-07-28
Packaged: 2018-07-22 02:14:19
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 4
Words: 2,364
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7415278
Author URL: https://archiveofourown.org/users/IntrovertedbutBooksmart/pseuds/IntrovertedbutBooksmart
Summary: <blockquote class="userstuff">
              <p>Finally, the burden Sans had been carrying for so long,<br/>Lifted.</p><p>Well, he thought.</p><p>But something's definitely going on. It's hard to tell, but Frisk has been acting kinda different lately...<br/>like they're fighting something? It's weird.</p><p>{Hi! This is my first time really writing anything, so it's not that good, really. This takes place post True Pacifist, right after the genocide route.<br/>Constructive criticism always welcome! Encouraged, really.}</p>
            </blockquote>





	1. Nice day today~

**It's a beautiful day outside.**

**Birds are singing,**

**flowers are blooming.**

 

**It's on days like these,**

 

**That monsters like us....**

 

"*Should be enjoying the outdoors, maybe having a picnic together!" Toriel Dreemurr, former queen of monsters, set a cinnamon-butterscotch pie upon a cooling rack, steam curling from its surface. She, Sans, Papyrus, Undyne, Alphys, Frisk, Asgore, and even Flowey lived together in a home that they had put money together to build. It was nice, really, and though it took some time to adjust, things ended up working out for the best. The unmistakable smell of Toriel's cinnamon-butterscotch pie wafted through the house, grins forming upon the occupants' faces.

  Frisk nodded as a response to Toriel, as they weren't one for much talking. It was undoubtedly a nice, crisp day outside, as Halloween came from around the corner. It left everyone in a great mood, too. They wouldn't mind a picnic with the others, even Flowey. Frisk had come back for Flowey as soon as everyone settled into New Home. He pretty much lived in a flower pot, of course. Ever since they had met Asriel- the REAL Asriel- Frisk had made up their mind.

 They'd do absolutely everything possible to SAVE Flowey.

 

  Sans had been re-reading those blueprints again, writing down certain instructions and parts he needed. He'd have to go back out to the city to buy some materials, for sure, as he wasn't able to bring what he  _did_ have already done to the Surface. He was stressing out again, wasn't he? There was no need to, as Frisk had promised him so many times that they would never think of pressing that dreaded RESET button again. And yet, something nagged at the back of his mind. The distant smell of cinnamon-butterscotch pie came to his conscious, pulling him to reality. How long had he been working?

  Sans rolled up the blueprints, storing away the list and multiple notes, hoping that no one would ever find them. He really didn't want to keep this from the others, especially Frisk, but he  _had_ to. Placing the documents into a drawer, Sans turned off his light and went downstairs, where the others had began to gather as well. Usually, when Toriel made her cinnamon-butterscotch pie, it meant she probably had something to say. Sure enough, as soon as the monsters, including a small, white dog for some reason, she began to announce, "*It's such nice weather out, and I believe that we should all have a picnic, what with little wind and rain!" Papyrus nodded, and responded with his usual loud and confident tone, "THAT SOUNDS LIKE AN EXCELLENT IDEA, NOT-ACTUALLY-ASGORE! WILL THERE BE SPAGHETTI?" 

  Sans couldn't hold back a grin as his brother said this. Toriel was, of course, aware of his cooking skills, as both he and Undyne had 'helped' her make a cinnamon-butterscotch pie. It had been turned into a semi-liquid bowl of butterscotch, cinnamon dumped all over the top. Then they got Frisk to try it, though Toriel had tried to stop the two. Man, that kid sure is DETERMINED. They actually took a bite of the stuff, caked in cinnamon, and managed not to cough the powder out. Of course, as soon as Undyne and Papyrus went away in triumph, they had to cough up that cinnamon.

  Toriel nodded however, though her eyes gave a look of caution to the taller skeleton. "*Of course there will, Papyrus!" Papyrus gave a "Nyeh heh heh!" before she continued. "*We'll go tomorrow, if that's alright with everyone's schedule!" They responded with nods and 'yes' before Toriel began to give slices of pie to the monsters.

  For the first time in so long, Sans actually felt himself relax.

  Everything was fine. No RESETS. That means no more timelines like that  _last one._ His left eye glinted with a faint dark blue just from the thought of what had happened then.

 

  Frisk grinned practically ear-to-ear as they received a slice of cinnamon-butterscotch pie from Toriel. It was nice, knowing that it'd be like this, no more resetting.

  They made a promise that they intended to keep, to the very end.

  


	2. Something's Off

**Summary for the Chapter:**

> Frisk has been acting kinda weird lately. Not only are they looking a lot more tired, but it's like they're trying to stay away from the other monsters. Sans tries to figure out what's up.

**Notes for the Chapter:**

> Here, take these words.

  "*kid?"

  "*frisk?"

  Sans opened their door, which led to a nice, tidy room. Upon a shelf is where a flower pot stood, its occupant gazing out of the window, thinking. Flowey's face turned to a sneer as he entered. "*They're not here, smiley trashbag." Sans rolled his 'eyes'. Why weren't they here? Usually, they'd be talking to Flowey. Frisk mentioned something about SAVING him, but why?

  He shook his head and closed the door. They'd probably be downstairs, helping Toriel, right? Frisk  _has_ been acting really strange lately, though, and he just wanted to get to the bottom of it. Putting his bony hands into his jacket's pockets, he made his way downstairs. Sure enough, Toriel was in the kitchen, humming a familiar tune as she cleaned up from the pie she had made earlier. Frisk wasn't there.

 

  Frisk shivered. Why had it been so cold here? It was hardly fall, after all. But it felt like the temperature had just gone down 10 degrees. Maybe it was- "*No.... don't think about them." They whispered. Chara wouldn't hurt anyone, not after that last timeline. Though, true, Chara was trying so hard to hurt the others, Frisk had more DETERMINATION. 

  Where were they, anyway? Frisk just went outside to take a walk to get their mind off of things and enjoy the sunset. They didn't take any weird turns or anything. There was a dot of light in the distance, which grew larger as they walked towards it, the all-too-familiar cave around them dark. Nobody's been here for a long time. As they approached, the once golden light outside turned to a dark twilight. Toriel would probably be looking for them by now.

 

  Sans watched the sun sink below the horizon, his brother walking towards their home next to Undyne, both carrying bags of groceries. Toriel had gone out searching for Frisk, which had only made him all the more worried. She said it was a possibility that they had gone back to MT. Ebott, as they lived not far from it, and they were walking in that direction last. He had offered to come, though she said that he should stay with the others just in case they come back. It was clear, however, that she just wanted to go alone.

  He stood up and went over to the two monsters, taking a couple of the heavier bags and getting them inside. No words were spoken, as there was a heavy atmosphere, like something had happened. Sans carried the bags to the kitchen, where he and Papyrus put away the ingredients and set aside several things for the others. It was odd to see the taller skeleton quiet. "*what's goin' on, bro?" He asked, noting the others' hesitation. "I.. DO NOT KNOW, BROTHER. IT'S LIKE SOMETHINGS OFF. BUT NOTHING'S WRONG, RIGHT?" Sans shrugged. Toriel has been out for a bit longer than he expected. She was just looking for Frisk, right? So why was something nagging the back of his mind so much..? 

 

  Frisk knew they did something wrong. Why had they seemingly blacked out and ended up here? Why was it so late?

  ...Why was there dust on their hands?

 


	3. Woken.

**Summary for the Chapter:**

> ...Toriel's been gone for too long, Sans knew. Luckily, Frisk finally calls and lets him know where they are. But something's so wrong. With the burning feeling of worry in his soul, Sans and Undyne set out to find Frisk.  
>  But he forgot about the machine.

**Notes for the Chapter:**

> Sorry about the shorter chapters.   
> Enjoy more words, tho.

_(*Ring, ring...)_

Sans picked up the phone the moment it went off. Toriel's been gone for a long, long time now, and it was getting uncomfortable for everyone to wait. Did something happen? When he checked the number, he realized it was Frisk. Sighing with relief, he answered. "*heya, kid. where have you b-" He was cut off by a small, scared voice. "*S- Sans, something happened..." He stood up immediately, opening his door and rushing down the stairs, not bothering to turn off his lights or stow away his documents.

 

  Undyne, who had resided in the room next to Sans's, heard him speeding down the steps. What was he doing up this late? She had been waiting downstairs in case Frisk or Toriel showed up, and just came in to check on Alphys, who had some rare nightly terrors from her experience with the Amalgamations. Undyne hated seeing her hurt from that...

  She opened the door quietly, only to find Sans running downstairs. He was holding a phone and wearing a distressed expression. "*Sans!" She said in a quiet voice, not wanting to awaken the home's occupants. "*What's wrong?" He turned to her immediately, replying with the same voice. "*frisk." She didn't need anymore convincing. Undyne nodded, closing the door softly and following the skeleton downstairs. She wouldn't take no for an answer, and Sans wouldn't deny help, she knew.

 

"*where are you?" It was comforting, to say the least, hearing Sans's surprisingly calm voice, though it seemed evident he was running down the stairs. Frisk wasn't expecting him to still be awake, but they were happy he was. "*MT. Ebott," they replied, hoping he'd get there quick. They had this burning feeling of guilt and terror in their soul. What had they done? The only thing they remembered was Toriel... then dust. It scared them thinking about what happened, what Chara had made them do. The worst part was that the dust refused to stay off of their clothes, only reminding them.

"*jeez, kid. how'd you end up there?" Frisk didn't want to reply. Chara's influence was whispering for them to attack. _"*Kill them... kill them all..."_ There was just that whisper in the back of their head, trying to overpower Frisk's MERCY. They shook their head, trying to will the other away, though in vain.

 

Sans arrived at the bottom of MT. Ebott, panting, having run almost all the way, though Undyne had hardly broken a sweat. Frisk must've been at the end of the cave, where the barrier once was. They started up the mountain, as fast as the two could go. Where was Toriel? ...Did something happen to her? Sans shook his head. She's perfectly fine, probably with Frisk, right? He and Undyne came upon the dark entrance, looking for the human. They didn't dare shout the name, though. If something was there that wanted to hurt Frisk, they didn't want to attract attention to themselves or the kid.

 

  Now, Gaster himself wasn't one to enjoy rude awakenings like, oh, dying but ending up in the void, and then being forced back into reality somehow. But it wasn't the worst thing in the world to come back to life, many years after death. He was in what seemed to be a basement when he came to, though where, he wasn't sure. There was that machine he had stopped working on long before falling into the CORE. How was it working? ...Was it his son?

  Definitely a possibility, he thought as he took a look around him. Notes and some blueprints were scattered on the tables and the floor. Yep, this was Sans. But how had he gotten this to work, and where was he? This didn't  _feel_ like the Underground. The air seemed so fresh to him. Could he be on the surface, perhaps? Another possibility, for sure. He hadn't seen much since he fell.

  


	4. Flee to Protect

**Summary for the Chapter:**

> .  
> .  
> .  
>  *5 Left

   _*Murderer_

_*Coward_

_*Fool_

The words echoed through their mind as they ran from the voices that called their name. They had to stay away from the monsters. Frisk was a danger to them all.

  They deeply regret calling Sans to them. If, no, when he found out what they had done, they were going to be in trouble. Frisk dropped the knife they didn't remember picking up into a bed of golden flowers, hiding it from view. 

  As they went on, the voices slowly faded. Frisk eventually arrived at the CORE, but didn't plan on stopping. It was dark here, as most of the power in the Underground had been switched off, buildings abandoned. 

 

  "*Frisk!" Undyne's voice echoed throughout the empty Throne Room. She didn't even realize she stepped in a pile of dust until Sans pointed it out to her. 

"*is that... tori..?" His hand shook as he stared at the dust, expressionless. Undyne stumbled back from it, her spear dropping from her hand. "*That's not.. possible! Who would-!" She growled in anger as she went through her mind for any culprits. It couldn't have been Frisk, for sure! Her opinion was very, very strong on that. 

  She took another step back, into the large bed of golden flowers.

 

  Frisk slowed down to a walk, sure that their friends were behind and not following. Luckily, the elavators were still powered and working. Within minutes, they were at MTT resort. 

  Not many monsters stayed behind in the Underground, though sometimes humans came by to explore. Right now, however, not many have visited, so the Underground was mostly empty.

  Mostly.

 

  Asr- Flowey didn't have a soul. He couldn't feel emotion. Couldn't care. Couldn't hurt. Couldn't even be angry. But Flowey knows when something's up. It's hard to sneak anything by him. Not even Frisk was able to slip by. Flowey didn't care for Frisk, but he owed them. They let him feel love again, even for just a few minutes. And Asriel never let a debt go unpaid.

  That's why when Frisk came back from helping Toriel just before they went missing, Flowey couldn't help but ask what was wrong. He knew their expression all too well--

  Trapped.

  "*Alright, Frisk, what happened?" He asked, voice empty. "*What do you mean, Asriel?" Frisk put that fake smile back on, but Flowey could see right through it. "*You know what I mean. What's wrong?" Frisk shook their head. "*Nothing! I'm alright." If Flowey had eyebrows, one would be raised. It was unusual for them to lie. Maybe... "*Is it about...

  Chara?"

  Frisk signed. "*I'm going to... take a walk." So Flowey was right. But what exactly was up?

 

  Gaster wasn't sure what to do. Surely, there'd be questions if he were to leave, but he wasn't sure about staying in this basement. What if somneone found him here? Unfortunately, that question was answered as soon as it was asked when he heard a door opening.

  

**Author's Note:**

> Welp?


End file.
